Illumination device

ABSTRACT

An illumination device configured to emit illumination light has a light source arranged inside a housing generating the illumination light; a diffusing panel attached to the housing; and a projector arranged inside a space formed by the housing and a part of the diffusing panel for projecting an image onto a projection surface. An optical unit is arranged so that an incident direction of a light flux incident from a display element provided in the projector onto a projection optical system of the projector is substantially vertical or in a direction closer to a vertical direction than a direction parallel to a horizontal plane, or so that an optical axis of the projection optical system on which the light flux from the display element provided in the projector is incident is substantially vertical or in a direction closer to the vertical direction than the direction parallel to the horizontal plane.

TECHNICAL FIELD

The present invention relates to an illumination device.

BACKGROUND ART

Patent Document 1 listed below discloses a technique of attaching acommunication functional module, which can utilize various functions byattaching it to a ceiling or a wall surface, to a ceiling light.

Furthermore, Patent Document 2 listed below discloses an illuminationdevice equipped with an image projection device capable of the spaceproduction using illumination light and an image in combination.

RELATED ART DOCUMENTS Patent Documents

Patent Document 1: Japanese Unexamined Patent Application PublicationNo. 2003-16831

Patent Document 2: Japanese Unexamined Patent Application PublicationNo. 2012-186118

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

However, the conventional techniques mentioned above just disclose ablock diagram and a simple external shape of a projector, and do notdisclose the layout of an optical system and an optical element of theprojector in the illumination device or the layout of an optical unit inconsideration of the arrangement of the optical system and the opticalelement. Thus, the consideration of an effective arrangement between anillumination light source in the illumination device having the imageprojection function and the optical unit of the projector serving as theimage projection function has been still insufficient.

Therefore, the present invention has been achieved in consideration ofthe problems in the conventional techniques mentioned above, and anobject of the present invention is to provide an illumination device inwhich a light source used for an illumination function and an opticalunit used for an image projection function are suitably arranged.

Means for Solving the Problems

In order to achieve the object mentioned above, according to the presentinvention, an illumination device includes: a light source arrangedinside a housing and generating the illumination light; a diffusingpanel attached to a part of the housing and diffusing the illuminationlight from the light source; and a projector arranged inside a spaceformed by the housing and a part of the diffusing panel and projectingan image onto a projection surface, and an optical unit constituting theprojector is arranged in a state where an incident direction of a lightflux incident from a display element provided in the projector onto aprojection optical system of the projector is a substantially verticaldirection or a direction closer to a vertical direction than a directionparallel to a horizontal plane, or in a state where an optical axis ofthe projection optical system on which the light flux from the displayelement provided in the projector is incident is a substantiallyvertical direction or a direction closer to the vertical direction thanthe direction parallel to the horizontal plane.

Effects of the Invention

According to the present invention, it is possible to provide anillumination device in which a light source used for an illuminationfunction and an optical unit used for an image projection function aresuitably arranged.

BRIEF DESCRIPTIONS OF THE DRAWINGS

FIG. 1 is a perspective view showing an external appearanceconfiguration of a pendant-type illumination device according to oneembodiment of the present invention together with a usage environmentthereof;

FIG. 2 is a perspective view showing an external appearanceconfiguration of a ceiling-type illumination device according to oneembodiment of the present invention together with a usage environmentthereof;

FIG. 3 is a view showing the illumination device seen from below, inwhich a part of a diffusing panel is removed in order to show aninternal configuration thereof;

FIG. 4 is a view showing a specific example of an illumination lightsource in the illumination device;

FIG. 5 is a view for describing a retainer for hanging the pendant-typeillumination device from a ceiling surface;

FIG. 6 is a block diagram showing an internal circuit configuration ofan optical unit of the illumination device in detail;

FIG. 7 is a side view for defining a vertical orientation which is aplacement of the optical unit in the illumination device;

FIG. 8 is a perspective view for defining the vertical orientation whichis a placement of the optical unit in the illumination device;

FIG. 9(A) and 9(B) area side view and a bottomview for describing anembodiment of the layout (arrangement) of the optical unit and theillumination light source in a housing of the pendant-type illuminationdevice;

FIGS. 10(A) and 10(B) are a side view and a bottom view for describinganother embodiment of the layout (arrangement) of the optical unit andthe illumination light source in the housing of the pendant-typeillumination device;

FIGS. 11(A) and 11(B) are a side view and a bottom view for describinganother embodiment of the layout (arrangement) of the optical unit andthe illumination light source in the housing of the pendant-typeillumination device;

FIGS. 12(A) and 12(B) are a side view and a bottom view for describing amodification example of the layout (arrangement) of the optical unit andthe illumination light source in the housing of the pendant-typeillumination device;

FIGS. 13(A) and 13(B) are a side view and a bottom view for describinganother modification example of the layout (arrangement) of the opticalunit and the illumination light source in the housing of thependant-type illumination device;

FIGS. 14(A) and 14(B) are a side view and a bottom view for describinganother modification example of the layout (arrangement) of the opticalunit and the illumination light source in the housing of thependant-type illumination device;

FIGS. 15(A) and 15(B) are a side view and a bottom view for describinganother modification example of the layout (arrangement) of the opticalunit and the illumination light source in the housing of thependant-type illumination device;

FIG. 16 is a side view for describing another modification example ofthe layout (arrangement) of the optical unit and the illumination lightsource in the housing of the pendant-type illumination device;

FIG. 17(A) and 17(B) are a side view and a bottom view for describing anembodiment of the layout (arrangement) of the optical unit and theillumination light source in a housing of the ceiling-type illuminationdevice;

FIGS. 18(A) and 18(B) are a side view and a bottom view for describinganother embodiment of the layout (arrangement) of the optical unit andthe illumination light source in the housing of the ceiling-typeillumination device;

FIGS. 19(A) and 19(B) are a side view and a bottom view for describinganother embodiment of the layout (arrangement) of the optical unit andthe illumination light source in the housing of the ceiling-typeillumination device;

FIGS. 20(A) and 20(B) are a side view and a bottom view for describing amodification example of the layout (arrangement) of the optical unit andthe illumination light source in the housing of the ceiling-typeillumination device; and

FIG. 21 is a side view for describing another modification example ofthe layout (arrangement) of the optical unit and the illumination lightsource in the housing of the ceiling-type illumination device.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Hereinafter, embodiments of the present invention will be described indetail with reference to the attached drawings.

<Pendant-Type and Ceiling-Type Illumination Devices Equipped with ImageProjection Function>

First, FIGS. 1 and 2 each illustrate an external appearanceconfiguration of an illumination device equipped with an imageprojection function according to one embodiment of the presentinvention. In particular, FIG. 1 illustrates the illumination deviceequipped with an image projection function, in which an image projectionfunction is mounted on a so-called pendant-type illumination deviceattached in the form of being hung from a ceiling surface. FIG. 2illustrates the illumination device equipped with an image projectionfunction, in which an image projection function is mounted on aso-called ceiling-type illumination device attached to a ceilingsurface.

As is obvious from the figures, the illumination devices 10 and 10′ eachequipped with the image projection function are attached onto a wallsurface or a ceiling 50 constituting a space such as a kitchen, a diningroom, a living room or an office when in use. More specifically, asillustrated in the figures, the illumination device is installed at apredetermined height above a table or a desk 60 placed in a room orinstalled integrally with the ceiling surface. The illumination devices10 and 10′ equipped with the image projection function each have both anillumination function of irradiating the upper surface of a table or adesk with illumination light and the image projection function ofprojecting and displaying various images onto an upper surface (displaysurface or projection surface) 61 of the table or the desk 60. Note thata reference character 40 in FIG. 1 particularly denotes a retainer forretaining the pendant-type illumination device 10 in the state of beinghung at a desired position from the ceiling surface.

A horizontal plane of a table or a desk onto which an image is to beprojected by the image projection function is likely to be an objectilluminated by the illumination function when the image projectionfunction is not used. Therefore, it is desirable that a region ontowhich an image is projected by the image projection function and a rangeto be illuminated with the illumination light of the illuminationfunction are at least partially overlapped with each other.

Also, the illumination device equipped with the image projectionfunction is desirably configured to include a control unit so that theillumination light of the illumination function and the image projectedby the image projection function are individually turned ON and OFF.

FIG. 3 illustrates an example of an internal configuration of thependant-type illumination device 10 equipped with the image projectionfunction illustrated in FIG. 1. As is obvious from the figure, though described later in detail, an illumination light source 20 including aplurality of semiconductor light-emitting elements (LED) arranged in aplanar form (here, illustration of each semiconductor light-emittingelement is omitted and an attached position thereof is indicated with abroken-line circle) and a small-sized projector for projecting anddisplaying various images, in particular, a projector optical unit(optical engine) 30 which is a main unit constituting the projector areprovided in a substantially cylindrical or conical main body (orreferred to also as a housing) (shade) 11 made of synthetic resin formedby die molding.

Note that a reference character 12 in the figure denotes a so-calleddiffusing panel which is provided to cover a lower opening of the mainbody 11 and uniformly irradiate the illumination light downward bydiffusing the illumination light from the illumination light source 20.Note that the external shape of the main body (shade) 11 has beendescribed as being cylindrical or conical, but the present invention isnot limited to this, and other shapes such as a box type may beprovided.

Note that, though not illustrated here, it is needless to say that aninternal configuration of the ceiling-type illumination device 10′equipped with the image projection function illustrated in FIG. 2 alsoincludes an illumination light source including a plurality ofsemiconductor light-emitting elements (LED) arranged in a planar form,an optical unit constituting a small-sized projector for projecting anddisplaying various images, and a diffusing panel in a main body (housingor shade) made of synthetic resin formed by die molding like thependant-type illumination device equipped with the image projectionfunction described above. Also, the external shape of the main body(shade) has been described as being a quadrangular box-type in theexample of FIG. 2, but the present invention is not limited to this, andother shapes such as a circular plate and an elliptical plate may beprovided.

FIG. 4 illustrates a specific example of the illumination light source20 described above, and the figure is a bottom view of the pendant-typeillumination device 10 equipped with the image projection function inFIG. 1 seen from below in a state where the diffusing panel 12 isremoved. As is obvious from the figure, for example, a plurality ofsemiconductor light-emitting elements (LED) 22 (ten elements in thisexample) are arranged and attached on a surface of a disk-shaped board21 made of, for example, metal having superior thermal conductivity sothat the substantially uniform irradiation light can be acquired. Inorder to easily understand a structure, the illumination device 10equipped with the image projection function in which the diffusing panel12 is removed is illustrated in the following figures in which theillumination device 10 is viewed from below.

Note that, though not illustrated here, the diffusing panel 12 describedabove is made by a transparent or translucent member that scatters theirradiation light so as to cover the opening below the illuminationlight source 20, and an aperture or a transmissive window 14 that is atransparent window for transmitting image light is formed in a part ofthe diffusing panel 12, namely, at a position through which the imagelight is projected from the optical unit 30 of the projector.

In addition, though described later, in order to achieve an interactivefunction of the optical unit, a camera may be provided as a sensorattached to a part of the optical unit. Note that the camera isconfigured to detect an infrared light component in an imaging rangeincluding the display surf ace 61, and it is thus possible to detect theoperation content of a user by capturing a motion of the user ordetecting reflected light from an object operated by the user.

Here, as illustrated in FIG. 1, the retainer 40 for retaining the mainbody 11 of the pendant-type illumination device 10 equipped with theimage projection function in the state of being hung at a desiredposition from the ceiling surface is fixed to the upper surface of theillumination device 10 equipped with the image projection function. Theretainer 40 will be described below with reference to FIG. 5.

Namely, one end (lower end) of the retainer 40 is fixed to a bottomsurface (upper end surface) constituting the main body 11 of theillumination device 10 equipped with the image projection function, anda disk-shaped attachment 45 for fixation to the ceiling surface isprovided at the other end (upper end) of the retainer 40, so that thedisk-shaped attachment 45 is securely fixed to the ceiling surface with,for example, screws 46 and threaded holes 47.

Note that, according to the studies by the inventors for theillumination device 10 equipped with the image projection functioncapable of not only irradiating the upper surface of a table or a deskwith the illumination light but also projecting and displaying an imageonto the table or the desk, it was found that a situation where aprojected image is shaken and the function as a display device cannot besufficiently achieved may occur when the main body 11 of theillumination device equipped with the image projection function swingsor rotates.

Therefore, in this example, the retainer 40 is formed of, for example, ahollow metal pipe made of aluminum, that is, a rigid member, so that apreferable result can be acquired. In this case, if the light source 20including the semiconductor light-emitting elements (LED), a power cord48 for supplying power to the optical unit 30, and a cable for supplyingan image signal as needed are housed inside the pipe constituting theretainer 40, it becomes unnecessary that the power cord and the cableare laid outside the pipe, and an illumination device equipped with animage projection function with superior design can be provided.

Further, if the pipe constituting the retainer 40 is configured so thatthe lower end thereof is open to an internal space of the main body 11of the illumination device equipped with the image projection function,namely, air inside the main body 11 of the illumination device equippedwith the image projection function can flow into the pipe of theretainer 40, heat generated from the light source 20 and the opticalunit 30 housed inside the main body can be guided into the pipe by aso-called chimney effect and discharged to the outside through a slitaperture 49 formed in an upper part of the pipe (see white arrows in thefigure). Accordingly, it is possible to contribute to the efficientcooling of the illumination device 10 equipped with the image projectionfunction.

Furthermore, though not illustrated here, a pipe obtained by coaxiallycombining a plurality of pipes having different diameters in a slidablemanner and providing a fixture at a part of the pipes so that the entirelength thereof is adjustable may be used as the pipe constituting theretainer 40. Accordingly, the height of the illumination device 10equipped with the image projection function hung from the ceiling 50 canbe flexibly adjusted, and it is thus possible to realize theillumination device equipped with an image projection function havingmore superior availability.

FIG. 6 is a block diagram showing an example of an internal circuitconfiguration of the optical unit 30, namely, the projection imagedisplay device in detail.

A projection optical system 101 (reference character 34 in FIG. 3) is anoptical system that projects an image onto the display surface 61, andincludes a lens and/or a mirror. A display element 102 (referencecharacter 32 in FIG. 3) is an element that generates an image to beprojected, and a transmissive liquid crystal panel, a reflective liquidcrystal panel, a digital micromirror device (DMD: registered trademark)or the like is used as the display element 102. A display element driveunit 103 transmits a drive signal in accordance with an image signal tothe display element 102. Alight source 105 (reference character 31 inFIG. 3) generates illumination light for projection, and a high-pressuremercury lamp, a xenon lamp, a LED light source, a laser light source orthe like is used as the light source 105.

A power source 106 supplies power to the light source 105. Anillumination optical system 104 condenses the illumination lightgenerated by the light source 105 so as to irradiate the display element102 with the uniformed illumination light. A cooling unit 115 coolsrespective units to be in a high-temperature state such as the lightsource 105, the power source 106 and the display element 102 as neededby the air cooling method or the liquid cooling method. An operationsignal input unit 107 is an operation button on the device body or alight-receiving unit for a remote controller, and inputs an operationsignal from a user.

An external image output device is connected to an image input unit 131to input image data from the external image output device.

An external image output device is connected to an audio input unit 133to input audio data from the external image output device. An audiooutput unit 140 is capable of performing audio output based on the audiodata input into the audio input unit 133. Also, the audio output unit140 may output a built-in operation sound or error alarm. Acommunication unit 132 is connected to, for example, an externalinformation processing device to input and output various controlsignals.

A non-volatile memory 108 stores data and display icons for variousoperations in the interactive function, data for calibration to bedescribed later, and other data used for the projector function. Amemory 109 stores image data to be projected and control data of thedevice. A control unit 110 controls the operation of each unit in thedevice. In particular, the control unit 110 controls a sensor 150 and aninteractive function unit 120 to execute the interactive function.

The sensor 150 can detect reflected light from an operated object bydetecting an infrared light component with a camera that captures arange overlapped with an image projection region on the display surface61. Note that, by setting the cut wavelength of an optical filter of thesensor 150 within a visible light wavelength region (for example,setting it within the red visible light region), a partial visible lightcomponent (namely, a projected image on a display screen) other thaninfrared light can be captured together with the infrared lightcomponent.

The interactive function unit 120 performs an interactive operation suchas writing of a character or a figure into an image region based on theoperation of a luminous pen or a finger by a user. Thus, the interactivefunction unit 120 includes a function of analyzing an infrared imageacquired from the sensor 150 to calculate the position of the luminouspen or the finger (position operated by the user) and a function ofexecuting applications operable with the luminous pen or the finger suchas an application that composites an operation icon in the projectedimage or performs drawing operation on the basis of the operation of theuser and an application that performs operation for an image input fromthe external image output device.

Here, the capturing range of the sensor 150 and the range of an imageprojected onto the display surface 61 (optical image in the image regionof the display element 102 on the display surface 61) do not agree witheach other. Therefore, when calculating the position operated (drawn) bythe user, conversion between coordinates in the capturing range of thesensor 150 and coordinate positions in the image projected onto thedisplay surface 61 is needed. Thus, the interactive function unit 120includes a function of performing the process for the conversion and afunction of performing the process of generating conversion table data(calibration data) for the conversion process.

An external image output device is connected to the image input unit 131to input image data from the external image output device. An externalimage output device is connected to the audio input unit 133 to inputaudio data from the external image output device. The communication unit132 is connected to, for example, an external information processingdevice to input and output various control signals.

Note that, in the example described above, as illustrated in FIG. 3, thelight from the light source 31 of the optical unit 30 (for example,semiconductor light-emitting element (LED)) is modulated into imagelight by the display unit 32 configured of a reflective image displayelement such as a digital micromirror device (DMD: registered trademark)(or transmissive image display element such as a liquid crystal panel),and the image light is projected to the outside through the projectionoptical system 34 including various lenses.

Namely, the image projected downward from the optical unit 30 isdisplayed in a range at least partially overlapped with a region ontowhich the illumination light can be irradiated by the illuminationdevice 10 equipped with the image projection function below the opticalunit 30. Note that the details of the optical unit 30 will be describedlater again. Prior to this, however, the positional relationship betweenthe optical unit 30, the illumination light source 20, and the diffusingpanel 12 inside the main body (shade) 11 of the illumination device 10equipped with the image projection function will be described below.

Also, for example, the circuit configuration illustrated in FIG. 6 maybe assembled on a circuit board and arranged inside the optical unit 30,or may be arranged outside (for example, on the back surface of thedisk-shaped board 21 on which the illumination light source 20 to bedescribed in FIG. 10 and thereafter is arranged).

<Definition of Placement of Projector Optical Unit>

Here, the placement of the optical unit (30) constituting the projectoris defined as follows in the present specification.

<Vertical Orientation of Optical Unit>

As illustrated in FIGS. 7 and 8, in a case where a light flux from thedisplay element (reference character 32 of FIG. 3) constituting theprojector is incident on the so-called projection optical system (34)including various optical elements such as a lens, the verticalorientation of the optical unit indicates the state where the incidentdirection of the light flux or the optical axis of the projectionoptical system (34) on which the light flux is incident is arranged in asubstantially perpendicular direction relative to a horizontal plane(plane perpendicular to the surface of the figure) or is arranged in adirection closer to a vertical direction than a direction parallel tothe horizontal plane. Note that a z direction is the vertical direction,that is, the direction perpendicular to the horizontal plane in FIGS. 7and 8.

With the layout described above, light emitted from the projectionoptical system (34) can form an optical image of the display element(32) onto the horizontal plane. Though not illustrated here, variouslayouts are available for an optical system from the light source (31)to the display element (32), and examples of the display element (32)include a transmissive type and a reflective type. In addition, variousoptical systems such as that having a layout including one unit of thedisplay element (32) and that having a layout including a plurality ofdisplay elements are known.

However, in a case where an optical unit case is to be miniaturized withthe vertical orientation layout illustrated in FIGS. 7 and 8, the sizereduction of the optical unit in the z direction of the figure is noteasy in consideration of the layout of the display element (32) and theprojection optical system (34).

However, in the vertical orientation layout of the optical unit (30),the size reduction of the optical unit in a y direction is easy incomparison to the other directions. Therefore, in the case where theoptical unit case is to be miniaturized with the vertical orientationlayout, the optical unit thinner in the y direction than in the zdirection is formed as illustrated in the perspective view of FIG. 8.

Note that, as indicated by broken lines in the figure, the position ofthe optical image of the display element on the horizontal plane can bevaried by changing a relative position setting on an xy plane betweenthe center position of the display element (32) and the optical axis ofthe projection system (34). Accordingly, the position of a projectedimage on the horizontal plane can be flexibly set in accordance with theneed in design.

Subsequently, more specific layouts (arrangements) of the pendant-typeillumination device 10 equipped with the image projection function inwhich the optical unit (30) is provided in accordance with the verticalorientation layout described above will be described below withreference to FIGS. 9 to 11.

<Pendant-Type Illumination Device Equipped with Image ProjectionFunction>

First, FIGS. 9(A) and 9(B) are a side sectional view and a bottom viewof the pendant-type illumination device 10 equipped with the imageprojection function. In this example, the board 21 of the illuminationlight source 20 including the plurality of semiconductor light-emittingelements (LED) 22 is attached to an inner bottom surface of the housing(shade) 11 serving as a main body. Furthermore, the diffusing panel 12is attached to the housing so as to cover an opening plane on the lowerside of the figure. In addition, the optical unit 30 is arranged so asto be located at a substantially center portion of an illumination lightflux in a space formed by the housing (shade) 11 and the diffusing panel12.

In the example of FIG. 9(A) and 9(B), an aperture or a transmissivewindow 14 is provided in the diffusing panel 12 at the position wherethe projection light is emitted downward from the optical unit 30. Thisis because, if the aperture or the transmissive window is not providedand the entire surface of the diffusing panel 12 has a diffusing effect,a projection image emitted from the optical unit 30 is also diffused andthe image cannot be formed on a surface on which the image is to beprojected such as a table or a desk. The aperture or the transmissivewindow 14 may be an opening obtained by cutting the diffusing panel 12or may be a transparent material having no diffusing effect such asglass.

In the case where the transmissive window is formed of the transparentmaterial, a configuration in which dust and others barely enter insidethe diffusing panel 12 can be provided. However, in order to prevent theprojection image emitted from the optical unit 30 from being affected asmuch as possible, it is preferable to provide the coating whose spectralcharacteristics are flat as much as possible in a wavelength region ofthe projection light emitted from the optical unit 30.

Note that the periphery of the aperture or the transmissive window 14 isnot necessarily directly coupled to the diffusing panel 12, and a regionfor a decorative panel may be provided between the aperture or thetransmissive window 14 and the diffusing panel 12 in order to make theshadow of the optical unit 30 difficult to be seen on the diffusingpanel 12. Namely, the aperture or the transmissive window 14 is anoutlet port or a transmission port necessary for emitting the imageprojection light projected from the optical unit 30 arranged in thespace formed by the housing (shade) 11 and the diffusing panel 12, andthe position thereof may be located in the diffusing panel 12 or a partof another component.

With the layout (arrangement) described above, since the optical unit 30can be thinned in a direction parallel to the horizontal plane, the rateof the shadow formed by the optical unit 30 to the illuminated area onthe diffusing panel 12 from the illumination light source 20 can bereduced. Accordingly, it is possible to suppress the degradation of thequality of appearance as an illumination device due to the influence ofthe shadow of the optical unit 30 formed on the diffusing panel 12(namely, sense of discomfort as an illumination device due to the shadowon the diffusing panel 12). Even in the case where the housing (shade)11 is formed of a diffusing panel, the shadow of the optical unit 30 isinconspicuous and it is possible to suppress the degradation of thequality of appearance as an illumination device.

Note that the diffusing panel 12 has an effect of diffusing the lightfrom the plurality of semiconductor light-emitting elements (LED) 22each having a small light-emitting area to convert the light intodiffusion light having more uniform light distribution characteristics.If the number of the semiconductor light-emitting elements (LED) 22 isincreased, more uniform diffusion light can be obtained, but thisresults in the cost increase. In the case where the number of theplurality of semiconductor light-emitting elements (LED) 22 is fixed,lights emitted from the semiconductor light-emitting elements (LED) 22arranged adjacent to each other are overlapped more as the distancebetween the plurality of semiconductor light-emitting elements (LED) 22and the diffusing panel 12 increases, so that more uniform diffusionlight is acquired. Therefore, it is preferable that the distance betweenthe plurality of semiconductor light-emitting elements (LED) 22 and thediffusing panel 12 is made as long as possible, in order to achieve bothcost performance and the acquisition of uniform diffusion light.

Meanwhile, since the projection optical system of the optical unit 30 isa magnifying projection system, the projection light projected downwardfrom the optical unit 30 is magnified as it travels downward. Thus, itis preferable that the distance between the position at which theprojection light is output in a downward direction from the optical unit30 (position at which the projection light is emitted downward from theprojection optical system 34 in the example of FIGS. 7 and 8) and theaperture or the transmissive window 14 is as short as possible. This isbecause, if the distance is increased, the area of the aperture or thetransmissive window 14 provided in a part of the diffusing panel 12needs to be increased due to the magnification of the image projectionlight, and the diffusing effect of the illumination light at that partcannot be acquired.

Accordingly, it is possible to suitably obtain the entire balancebetween the cost performance, the uniformity of the diffusion light, andthe miniaturization of the aperture or the transmissive window if theoptical unit 30 is provided in accordance with the vertical orientationlayout in the space formed by the housing (shade) 11 and the diffusingpanel 12 and the position at which the projection light is output in adownward direction from the optical unit 30 is located at a positionlower than the light source 20 as illustrated in FIGS. 9(A) and 9(B). Inthis manner, the distance can be secured between the plurality ofsemiconductor light-emitting elements (LED) 22 and the diffusing panel12, and the distance between the position at which the projection lightis output in a downward direction from the optical unit 30 and theaperture or the transmissive window 14 can be reduced, so that it ispossible to suitably obtain the entire balance between the costperformance, the uniformity of the diffusion light, and theminiaturization of the aperture or the transmissive window.

A similar effect can be acquired by providing a similar distancerelationship also in the cases illustrated in FIGS. 10(A) and 10(B),11(A) and 11(B), 12(A) and 12(B), 13(A) and 13(B), 14(A) and 14(B),15(A) and 15(B), 17(A) and 17(B), 18(A) and 18(B), 19(A) and 19(B) and20(A) and 20(B) to be described later. In this case, the position atwhich the image projection light is emitted from the optical unit 30 isarranged between the light source 20 and the aperture or thetransmissive window 14 with the arrangement in the vertical direction.

FIGS. 10(A) and 10(B) are a side sectional view and a bottom view of thependant-type illumination device 10 equipped with an image projectionfunction. In this example, the optical unit 30 attached inside thehousing (shade) 11 is arranged so as to be located at an end portion ofan illumination light flux.

With this layout (arrangement), it is possible to suppress thedegradation of the quality of appearance as an illumination device likein the example of FIGS. 9(A) and 9(B). Further, in the arrangement ofFIGS. 10(A) and 10(B), the optical unit 30 is arranged so as to belocated at the end portion of the illumination light flux, and furtherthe optical axis of a projection optical system and the center positionof a display element are relatively shifted in a horizontal directioninside the optical unit 30, so that the center of a projected image ismade to come close to the center of the illumination light flux of theillumination light source 20 with respect to an emission port of theprojection optical system of the projector.

Furthermore, in the arrangement of FIGS. 10(A) and 10(B) to be describedbelow, a so-called stationary projector which is usually placed on adesk for use can be directly applied. This is because the optical axisof a projection optical system and the position of the center of adisplay element are typically shifted in most of the stationaryprojectors. Therefore, the illumination device equipped with the imageprojection function of FIGS. 10(A) and 10(B) has a structure suitablefor cost reduction. This effect is acquired similarly in the otherexamples in which the optical unit 30 is located at the end portion ofthe downward illumination light flux.

Furthermore, as illustrated also in FIGS. 11(A) and 11(B), the opticalunit 30 can be arranged at an intermediate position between the layout(arrangement) of FIGS. 9(A) and 9(B) and the layout (arrangement) ofFIGS. 10(A) and 10(B). Also in this case, it is possible to suppress thedegradation of the quality of appearance as an illumination device likein the cases described above.

Furthermore, modification examples of the pendant-type illuminationdevice 10 equipped with the image projection function will be describedwith reference to FIGS. 12 to 16.

FIGS. 12(A) and 12(B) illustrate a configuration in which a center partof the board 21 for the illumination light source 20 provided with theplurality of semiconductor light-emitting elements (LED) 22 is foldedinto a substantially U shape to form groove portion 25 and the opticalunit 30 is arranged inside the groove portion (namely, located at asubstantially center portion of an illumination light flux). With thisconfiguration, since the optical unit 30 is arranged in the grooveportion 25, the shadow of the optical unit 30 itself is not directlycast below the diffusing panel 12 having a white surface, and it is thuspossible to further suppress the degradation of the quality ofappearance as an illumination device in addition to the effect of thevertical orientation of the optical unit. Note that an aperture (ortransmissive window) 26 for transmitting projection light from theoptical unit 30 is formed in a part of the groove portion 25, namely,the position at which the optical unit 30 is arranged.

In particular, by applying coating with high reflectance such as whitecoating or mirror coating to the outer surface of the groove portion 25(surface on the side opposite to the surface in which the optical unit30 is housed) from which illumination light from the plurality ofsemiconductor light-emitting elements (LED) 22 is reflected, it ispossible to suppress the shadow of the groove portion 25 itself frombeing formed on the diffusing panel 12.

The diffusing panel 12 may be provided on the bottom surface of thegroove portion 25, but the diffusing panel 12 is not necessarilyprovided to the portion of the bottom surface of the groove portion 25.In the example of FIGS. 12(A) and 12(B), the diffusing panel 12 isdivided into two sections by the bottom surface of the groove portion25.

FIGS. 13(A) and 13(B) illustrate a configuration in which the pluralityof semiconductor light-emitting elements (LED) 22 are arranged on bothsurfaces of the board 21 for the illumination light source 20. Namely,the configuration capable of irradiating illumination light upward aswell as downward is illustrated. Note that, in FIGS. 13(A) and 13(B),the optical unit 30 is arranged at an end portion of the illuminationlight flux of the downward illumination light, but the optical unit 30may be arranged at a center portion of the illumination light flux ofthe downward illumination light. With this configuration, theillumination light can be irradiated also to an upper side of theillumination device 10 equipped with an image projection function, andthe illumination device 10 equipped with the image projection functioncan function also as indirect illumination because the ceiling or thelike can be irradiated with the upward irradiation light (ceilingindirect illumination function). Note that, in this example, a diffusingpanel 12 (upper diffusing panel) is attached so as to cover an openingplane of the upper surface of the housing (shade) 11 in addition to thediffusing panel 12 (lower diffusing panel) for the opening plane of thelower surface of the housing (shade) 11.

In addition, by providing the configuration including the illuminationfunction having a plurality of different irradiation directions and theimage projection function, the switching between a plurality ofirradiation combination modes of the irradiation light and theprojection image can be achieved. For example, the switching control fora mode in which only the projection image is projected in a downwarddirection, a mode in which the irradiation light is irradiated downwardand the image is not projected, a mode in which the irradiation light isirradiated upward and the image is not projected, and a mode in whichthe irradiation light is irradiated upward and the projection image isprojected in the downward direction may be performed.

FIGS. 14(A) and 14(B) illustrate a configuration example in which theboard 21 for the illumination light source 20 is formed to have acylindrical shape by extending the end portion thereof in theperpendicular direction, a plurality of semiconductor light-emittingelements (LED) 22 are attached onto the bottom surface thereof, and aplurality of semiconductor light-emitting elements (LED) 22 are attachedalso onto the outer circumferential surface of the cylindrical board 21.Namely, the configuration capable of irradiating illumination lightsideward as well as downward is illustrated. Note that, in this example,the optical unit 30 is arranged so as to be located at a substantiallycenter portion of the downward illumination light flux. Note that theoptical unit 30 is not necessarily arranged at the substantially centerportion of the illumination light flux of the downward illuminationlight. The optical unit 30 maybe arranged on the end side of theillumination light flux of the downward illumination light, that is,near the side surface of the cylinder.

Also, a diffusing panel 12 (side diffusing panel) is attached also tothe outer circumference of the housing 11 in addition to the diffusingpanel 12 (lower diffusing panel) of an opening plane of the lowersurface of the housing 11. With this configuration, it is possible toirradiate the illumination light also in a sideward direction of theillumination device 10 equipped with an image projection function(wide-range illumination function) in addition to the effect of thevertical orientation of the optical unit.

In the example of FIGS. 14(A) and 14(B), the illumination functionhaving the plurality of different irradiation directions is providedlike in the example of FIGS. 13(A) and 13(B), and thus the switchingcontrol for a plurality of modes with respect to the illumination lightof the illumination function in the plurality of irradiation directionsand the projection image of the image projection function may beperformed as described in FIGS. 13(A) and 13(B).

In an example of FIGS. 15(A) and 15(B), the board 21 for theillumination light source 20 is formed to have a cylindrical shape byextending the end portion thereof in the perpendicular direction and tohave a flange portion by further extending the end portion in thehorizontal direction. Also, a plurality of semiconductor light-emittingelements (LED) 22 are attached to upper and lower surfaces of the board21, the outer circumferential surface of the cylindrical portion, andthe lower surface of the flange portion.

Note that the optical unit 30 is not necessarily arranged at asubstantially center portion of the illumination light flux of downwardillumination light. The optical unit 30 may be arranged on the end sideof the illumination light flux of the downward illumination light, thatis, near the side surface of the cylinder. Also, an opening is formed soas to cover the upper surface and a part of the outer circumference(upper portion) of the housing (shade) 11 and a diffusing panel 12(upper circumferential diffusing panel) is attached to the opening inaddition to the diffusing panel 12 (lower diffusing panel) of the lowersurface of the housing (shade) 11. With this configuration, theillumination light can be uniformly irradiated to the circumferenceincluding the upper surface and the lateral side of the illuminationdevice 10 equipped with an image projection function (wide-rangeillumination function) in addition to the effect of the verticalorientation of the optical unit.

In the example of FIGS. 15(A) and 15(B), the illumination functionhaving the plurality of different irradiation directions is providedlike in the example of FIGS. 13(A) and 13(B), and thus the switchingcontrol for a plurality of modes with respect to the illumination lightof the illumination function in the plurality of irradiation directionsand the projection image of the image projection function may beperformed as described in FIGS. 13(A) and 13(B).

FIG. 16 illustrates a configuration in which a planar luminous body 121such as electroluminescence (EL) is adopted instead of the board 21 forthe illumination light source 20 including the plurality ofsemiconductor light-emitting elements (LED) 22 in the configuration ofFIGS. 9(A) and 9(B) and the luminous body 121 is arranged at a lower endportion of the housing (shade) 11 (namely, at the position of thediffusing panel 12 of FIGS. 9(A) and 9(B)).

With this configuration, since the luminous body 121 covering the lowerend portion of the housing (shade) 11 in which the optical unit 30 ishoused irradiates illumination light, the optical unit 30 in the housing11 is not recognized from the outside, and it is possible to morereliably suppress the degradation of the quality of appearance as anillumination device. Note that, although only the case in which theoptical unit 30 is arranged to be located at an end portion of thedownward illumination light flux has been illustrated in this example,the arrangement is not limited to this. Even when the optical unit 30 isarranged at a substantially center portion thereof or at an intermediateposition therebetween, a similar effect can be achieved.

Also, although the luminous body 121 is provided so as to cover thelower end portion of the housing (shade) 11 in the example describedabove, a deep shade may be configured by extending a lower end portionof the side surface of the housing (shade) 11 in a downward directionbelow the luminous body 121.

Note that FIG. 16 corresponds to the case in which the plurality ofsemiconductor light-emitting elements (LED) 22 are removed from FIGS.9(A) and 9(B) and the planar luminous body 121 is arranged at theportion of the diffusing panel 12. Based on the similar idea, it is alsopossible to remove the plurality of semiconductor light-emittingelements (LED) 22 and arrange the planar luminous body 121 at theportion of the diffusing panel 12 in the configuration example of FIGS.13(A) and 13(B), FIGS. 14(A) and 14(B), or FIGS. 15(A) and 15(B). Inthis case, it is possible to realize an illumination device 10′ equippedwith an image projection function that includes the planar luminous body121 as an illumination function and is capable of irradiatingillumination light in a plurality of irradiation directions.Furthermore, since the illumination function having the plurality ofdifferent irradiation directions is provided like in the case of FIGS.13(A) and 13(B), the switching control for a plurality of modes withrespect to the illumination light of the illumination function in theplurality of irradiation directions and the projection image of theimage projection function may be performed as described in FIGS. 13(A)and 13(B).

Furthermore, more specific layouts (arrangements) of the ceiling-typeillumination device 10′ equipped with the image projection function inwhich the optical unit (30) is provided in accordance with the verticalorientation layout described above will be described below withreference to FIGS. 17 to 19.

<Ceiling-Type Illumination Device Equipped with Image ProjectionFunction>

First, FIGS. 17(A) and 17(B) are a side sectional view and a bottom viewof the ceiling-type illumination device 10′ equipped with an imageprojection function. In this example, the board 21 of the illuminationlight source 20 including the plurality of semiconductor light-emittingelements (LED) 22 is attached to an inner bottom surface of the housing(shade) 11 serving as a main body. Furthermore, the diffusing panel 12is attached to the housing so as to cover an opening plane on the lowerside of the figure. In addition, the optical unit 30 is arranged so asto be located at a substantially center portion of an illumination lightflux in a space formed by the housing (shade) 11 and the diffusing panel12.

With this layout (arrangement), since the optical unit 30 can be thinnedin a direction parallel to the horizontal plane, the rate of the shadowformed by the optical unit 30 to the illuminated area on the diffusingpanel 12 from the illumination light source 20 can be reduced.Accordingly, it is possible to suppress the degradation of the qualityof appearance as an illumination device due to the influence of theshadow of the optical unit 30 formed above the diffusing panel 12(namely, sense of discomfort as an illumination device due to the shadowon the diffusing panel 12). Even in the case where the housing (shade)11 is formed of a diffusing panel, the shadow of the optical unit 30 isinconspicuous and it is possible to suppress the degradation of thequality of appearance as an illumination device.

FIGS. 18(A) and 18(B) are a side sectional view and a bottom view of theceiling-type illumination device 10′ equipped with an image projectionfunction. In this example, the optical unit 30 attached inside thehousing (shade) 11 is arranged so as to be located at an end portion ofan illumination light flux.

Also, in the ceiling-type illumination device 10′ equipped with an imageprojection function illustrated in FIGS. 19(A) and 19(B), the opticalunit 30 is arranged at an intermediate position between the layout(arrangement) of FIGS. 17(A) and 17(B) and the layout (arrangement) ofFIGS. 18(A) and 18(B). Note that, with this layout (arrangement), it ispossible to suppress the degradation of the quality of appearance as anillumination device like in the cases described above.

Furthermore, in the configuration example of the ceiling-typeillumination device 10′ equipped with an image projection functionillustrated in FIGS. 20(A) and 20(B), the board 21 for the illuminationlight source 20 is formed to have a cylindrical shape by extending theend portion thereof in the perpendicular direction, a plurality ofsemiconductor light-emitting elements (LED) 22 are attached onto thebottom surface thereof, and a plurality of semiconductor light-emittingelements (LED) 22 are attached also onto the outer circumferentialsurface of the cylindrical board 21. Namely, the configuration capableof irradiating illumination light sideward as well as downward isillustrated. Note that, in this example, the optical unit 30 is arrangedso as to be located at a substantially center portion of the downwardillumination light flux. Note that the optical unit 30 is notnecessarily arranged at the substantially center portion of theillumination light flux of the downward illumination light. The opticalunit 30 may be arranged on the end side of the illumination light fluxof the downward illumination light, that is, near the side surface ofthe cylinder.

Also, a diffusing panel 12 (side diffusing panel) is attached also tothe outer circumference of the housing 11 in addition to the diffusingpanel 12 (lower diffusing panel) of an opening plane of the lowersurface of the housing 11. With this configuration, it is possible toirradiate the illumination light also in a sideward direction of theillumination device 10 equipped with an image projection function(wide-range illumination function) in addition to the effect of thevertical orientation of the optical unit. With the configurationdescribed above, it is possible to achieve the effect similar to that ofthe illumination device equipped with the image projection function ofFIGS. 14(A) and 14(B) in the ceiling-type illumination device equippedwith an image projection function.

In the example of FIGS. 20(A) and 20(B), the illumination functionhaving the plurality of different irradiation directions is providedlike in the example of FIGS. 13(A) and 13(B), and thus the switchingcontrol for a plurality of modes with respect to the illumination lightof the illumination function in the plurality of irradiation directionsand the projection image of the image projection function may beperformed as described in FIGS. 13(A) and 13(B).

Furthermore, in the configuration example of the ceiling-typeillumination device 10′ equipped with an image projection functionillustrated in FIG. 21, a planar luminous body 121 such aselectroluminescence (EL) is adopted instead of the board 21 for theillumination light source 20 including the plurality of semiconductorlight-emitting elements (LED) 22 in the configuration of FIGS. 18(A) and18(B) and the luminous body 121 is arranged at the position of thediffusing panel 12 of FIGS. 18(A) and 18(B). With this configuration,since the luminous body 121 covering the lower end portion of thehousing 11 in which the optical unit 30 is housed irradiatesillumination light, the optical unit 30 in the housing 11 is notrecognized from the outside, and it is possible to more reliablysuppress the degradation of the quality of appearance as an illuminationdevice.

Note that, although only the case in which the optical unit 30 isarranged to be located at an end portion of the downward illuminationlight flux has been illustrated in this example, the arrangement is notlimited to this. Even when the optical unit 30 is arranged at asubstantially center portion thereof or at an intermediate positiontherebetween, a similar effect can be achieved.

Note that FIG. 21 corresponds to the case in which the plurality ofsemiconductor light-emitting elements (LED) 22 are removed from FIGS.18(A) and 18(B) and the planar luminous body 121 is arranged at theportion of the diffusing panel 12. Based on the similar idea, it is alsopossible to remove the plurality of semiconductor light-emittingelements (LED) 22 and arrange the planar luminous body 121 at theportion of the diffusing panel 12 in the configuration example of FIGS.20(A) and 20(B), and further to divide the planar luminous body 121 intoa downward irradiation region and a sideward irradiation region inaccordance with the angle of the plane thereof.

In this case, if the light emission in the downward irradiation regionand the light emission in the sideward irradiation region of the planarluminous body 121 are made to be individually controllable, it ispossible to realize an illumination device 10′ equipped with an imageprojection function that includes the planar luminous body 121 as anillumination function and is capable of irradiating illumination lightin a plurality of irradiation directions. Furthermore, since theillumination function having the plurality of different irradiationdirections is provided like in the case of FIGS. 13(A) and 13(B), theswitching control for a plurality of modes with respect to theillumination light of the illumination function in the plurality ofirradiation directions and the projection image of the image projectionfunction may be performed as described in FIGS. 13(A) and 13(B).

In the foregoing, the illumination devices having the image projectionfunction according to the various embodiments of the present inventionhave been described. However, the present invention is not limited tothe embodiments described above, and includes various modificationexamples. For example, the entire system has been described in detail ineach of the embodiments in order to clearly describe the presentinvention, and the present invention is not necessarily limited to theembodiment including all the configurations described above. Also, apart of the configuration of one embodiment may be replaced with theconfiguration of another embodiment, and the configuration of oneembodiment may be added to the configuration of another embodiment.Furthermore, another configuration may be added to a part of theconfiguration of each embodiment, and a part of the configuration ofeach embodiment may be eliminated or replaced with anotherconfiguration.

REFERENCE SIGNS LIST

-   10 illumination device-   11 main body (housing) (shade)-   12 diffusing panel-   20 illumination light source-   22 semiconductor light-emitting element (LED)-   30 optical unit-   31 light source-   32 display unit-   34 projection optical system

1. An illumination device configured to emit illumination light, theillumination device comprising: a light source arranged inside a housingand generating the illumination light; a diffusing panel diffusing theillumination light from the light source; and a projector arrangedinside a space formed by the housing and a part of the diffusing paneland projecting an image onto a projection surface, wherein an opticalunit constituting the projector is arranged in a state where an incidentdirection of a light flux incident from a display element provided inthe projector onto a projection optical system of the projector is asubstantially vertical direction or a direction closer to a verticaldirection than a direction parallel to a horizontal plane, or in a statewhere an optical axis of the projection optical system on which thelight flux from the display element provided in the projector isincident is a substantially vertical direction or a direction closer tothe vertical direction than the direction parallel to the horizontalplane.
 2. The illumination device according to claim 1, wherein theprojector can project the image onto the horizontal plane as an imageprojection surface, and an image projection region of the projector onthe horizontal plane and an illumination range on the horizontal planeof the illumination light obtained by diffusing the light generated bythe light source are at least partially overlapped.
 3. The illuminationdevice according to claim 1, further comprising: an aperture or atransmissive window through which projection image light from theoptical unit is emitted from the inside of the space formed by thehousing and a part of the diffusing panel, wherein, in an arrangement inthe vertical direction, an emission position of image projection lightfrom the optical unit is arranged between the light source and theaperture or the transmissive window.
 4. The illumination deviceaccording to claim 1, wherein the illumination device is a pendant-typeillumination device.
 5. The illumination device according to claim 1,wherein the illumination device is a ceiling-type illumination device.6. The illumination device according to claim 1, wherein the opticalunit is arranged so as to be located at a center portion of illuminationlight flux from the illumination device.
 7. The illumination deviceaccording to claim 1, wherein the optical unit is arranged so as to belocated at an end portion of illumination light flux from theillumination device.
 8. The illumination device according to claim 1,wherein the optical unit is arranged so as to be located between acenter portion and an end portion of illumination light flux from theillumination device.
 9. The illumination device according to claim 1,wherein the light source includes a light-emitting element arranged andattached on a lower surface of a board attached to a part of thehousing.
 10. The illumination device according to claim 9, wherein theboard includes a side surface extending further from an end portion ofthe board in a perpendicular direction, and a light-emitting element isprovided on an outer side of the side surface.
 11. The illuminationdevice according to claim 1, wherein the light source includeslight-emitting elements each arranged and attached on a lower surfaceand an upper surface of a board attached to a part of the housing. 12.The illumination device according to claim 1, wherein the diffusingpanel is used as the light source that generates the illumination light.13. The illumination device according to claim 12, wherein the lightsource that generates the illumination light is configured of EL. 14.The illumination device according to claim 1, wherein the light sourcethat generates the illumination light is configured of a LED.